This invention relates to snap engagement fastening for quickly installed fasteners to secure two panels or sheets. In particular, it relates to panel fasteners which permit the manual securement and release of two panels or sheets.
The process of assembling equipment into racks involves attaching the equipment shelf to the side rails of a rack that has a series of vertically spaced rectangular holes in the side rails. Prior art fasteners for this type of rack system utilize a cage nut assembly, washer, and screw combination. This process requires that a cage nut be installed in the rack in the correct vertical position which requires a good deal of manual dexterity, and a special tool. Next, the shelf is placed so that the holes are aligned with the cage nut, and then manually held in place while a screw and washer are put into place and tightened. This operation needs to be repeated on both sides of the rack and two to four fastener assemblies may be required for each shelf. Removal of the shelf requires that all screws be removed and such loose screws and washers are then prone to be lost or fall into the sensitive electronic equipment. If retained threaded fasteners are used, each of them will require multiple turns by hand or with a tool for installation and removal. Thus, the present method of assembling rack systems is both time consuming and cumbersome. There is therefore a need to simplify the process of assembling equipment shelves to a rack having vertically spaced square holes.
The present invention significantly simplifies affixing an equipment shelf to the sides of the equipment rack. A novel snap-in fastener for rectangular holes has been developed which is permanently affixed to the shelf Attachment of the shelf is accomplished by merely snapping a the fastener into the rectangular holes in the side rails of the rack. Removal is accomplished by simply pulling on the shelf or the fastener itself There is no loose hardware that can be lost or cause damage to the equipment. While the present invention is an advancement in the art of assembling rack systems, the fastener disclosed herein is not limited to this specific application. It may be used in any application where panels need to be quickly secured without tools. This invention provides a fastener with several important features. First, the fastener has a clinch feature that provides permanent attachment to a first sheet of metal. Secondly, integral snap-arms provide a reusable means to attach the first sheet to an appropriately-sized rectangular hole in a second sheet. In addition, other optional features such as a locking mechanism and finger grips may be included.
The clinch attachment works by displacing metal from the first sheet into the undercut of the fastener. Once the metal has entered the undercut the part is permanently attached to the first sheet. The clinch profile and the overall envelope of the fastener can be sized for a wide variation of panel sizes and thickness.
The snap-arms include tapered barbs that allow the ends of the arms to initially engage the rectangular hole on the second sheet. With continued axial application of force, the arms flex inward and pass through the hole, at which point the arms return to their original position and thus retain the fastener in the hole. Pulling on the fastener or the shelf releases it in a similar manner.
A further embodiment of the fastener includes a locking mechanism. Once the second sheet has been engaged, a lock clip is pushed forward and snaps into place between the snap-arms thus preventing the fastener from loosening or being removed. This is accomplished by the lock clip acting as a positive stop to prevent the snap-arms from flexing inward and disengaging the hole in the second sheet. The fastener is then unlocked by simply pulling the lock clip into the unlocked position. In the unlocked position, the locking mechanism is out of the path of the flexing arm and allowing separation of the two sheets. The lock clip may include detents to ensure that the lock is held out of the path of the snap-arms while it is unlocked. The lock clip also prevents premature disengagement due to vibration. The lock clip may be molded from plastic, thereby providing a means of color identification and matching.
Another embodiment includes finger grips integral with the fastener. This allows parts of the fastener to function as a handle for the equipment. The extension of the fastener body is ergonomically designed and eliminates the need for additional hardware such as handles and/or knobs. Also by locating the finger grips directly behind the snap feature, the applied forces are directed axially, reducing lateral stresses on the fastener, thereby reducing the required force of assembly and disassembly.